Regenerator with expansible and contractible matrix



Jan. 23, 1968 3,364,984

R'EGENERATOR WITH EXPANSIBLE AND CONTRACTIBLE MATRIX C. H.' M CREARY 2Sheets-Sheet 1 Filed Oct. 27, 1966 C/zoif/z g ry Z M%%;RNYEY' Jan. 23,1968 c. H. M CREARY 3,354,984

REGENERATOR WITH EXPANSIBLE AND CONTRACTIBL E MATRIX Filed Oct. 27, 19662 Sheets-Sheet 2 IN VENTOR.

Czan/zn ii/c 02 Y ATTORNEY haw W United States Patent 3,364,984REGENERATOR WITH EXPANSIBLE AND CONTRACTIBLE MATRIX Charles H.McCrear-y, Oak Park, 11]., assignor to General Motors Corporation,Detroit, Mich., a corporation of Delaware Filed Oct. 27, 1966, Ser. No.589,921 13 Claims. (Cl. 165-6) My invention is directed to regenerators,which are devices in which a porous structure such as a disk, drum, orband is moved through two spaces divided from each other by a bulkheadand in which two different fluids flow through the matrix at each sideof the bulkhead so that one fluid gives off heat to the matrix and theother absorbs heat from the matrix. Devices of this sort have beenemployed as furnace air pre-heaters and as regenerators in gas turbineengines, in each case transferring heat from hot exhaust gases to airprior to its entry to the combustion apparatus. However, regeneratorsare usable for various heat transfer purposes.

One problem with regenerators of this sort lies in the fact that gasesare carried from one space to the other within the porous matrix. Thus,in a furnace some of the incoming air would be diverted to the stack andsome flue gases would be mixed with the incoming air. The carry-throughof gas becomes a more serious problem as pressure increases. In a gasturbine, for example, ap preciable quantities of compressed air arecarried by the matrix into the turbine exhaust and energy is thuswasted.

The basic point of my invention lies in the use of a matrix of anexpandable and contractible nature; for example, a material havinghoneycomb-like cells which may be flattened or opened out. The matrix isat least partially collapsed at the point where it passes through thebulkhead from one space to the other, thus purging it of much of the gaswhich otherwise would be carried through in the cells of the matrix.

Another highly significant point of my invention lies in the fact thatthe matrix is flexible rather than rigid and thus may move in a suitableway or track of almost any configuration, with a varying degree ofcurvature, and with straight runs if desired.

A further significant but optional aspect of my invention lies in meansfor limiting the expansion and contraction of the matrix and fortransmitting drive tension so that the driving load is carriedindependently of the cellular structure of the matrix.

The principal objects of my invention are to improve the efliciency ofregenerators, to minimize carry-through of gas in such devices, and toprovide a flexible matrix adapted to travel in paths of varyingcurvature.

The nature and advantages of the invention will be clear from thesucceeding detailed description of preferred embodiments of theinvention and the accompanying drawings.

FIGURE 1 is an axonometric view of a regenerator with parts cut away.

FIGURE 2 is a partial sectional view taken on the plane indicated byline 2-2 of FIGURE 1.

FIGURE 3 is a view similar to FIGURE 2 showing a modified structure.

FIGURE 4 is a sectional view taken on the plane indicated by line 4-4 ofFIGURE 3.

The particular embodiment of the invention described herein is intendedas an after-cooler for a compressor, but devices of the same charactermay be used for other purposes.

The regenerator comprises a housing 6 within which is mounted a matrix7. Housing 6 defines an inlet 9 and outlet 10 for one medium which flowsin a generally straight line through the matrix. The upper and lowerparts of the housing define spaces 11 and 12 for the second medium. Thematrix moves in a path which comprises two straight runs joined by twosemi-circular runs at each end, or what might be called a race-trackpath, being guided in shallow channel tracks 16 and 17 at the ends ofthe matrix which are supported on the housing. The matrix itself, as isapparent from the drawings, is a continuous band or belt and, as shownmost clearly in FIGURE 4, is of a honeycomb-type structure definingcells or passages 18 extending through the matrix from the inner to theouter side. The matrix is made of flexible material such as very thinshim stock which is formed into a corrugated pattern. Each leaf 19 ofthe matrix is formed with corrugations extending from the inner to theouter side of the matrix, and the corrugations on the adjacent leavesare relatively reversed so that, when the leaves are placed together anexpandable and contractible honeycom'bed structure somewhat analogous tothat of paper Christmas tree ornaments results. With this sort ofstructure, if the web or band is put in tension the leaves flex and thecells or passages 18 are opened. Longitudinal forces compressing thematrix tend to close the cells.

In the preferred embodiment of the invention, the matrix is slowly movedthrough seals where it passes from one medium to the other and ispropelled by rollers immediately ahead of the seals. The friction of theseals causes the matrix cells to collapse as they enter the seal and thetraction of the next set of driving rollers opens the cells as they passthrough the run from one seal to the next.

Referring now to FIGURES l and 2,, the stationary structure of theregenerator includes an upper bulkhead or diaphragm 19 and acorresponding lower diaphragm 20 which provide a passage interconnectingthe inlet 9 and outlet 10 and passing through both the straight runs ofthe matrix. The second medium flows radially through both thesemicylindrical end portions of the matrix. This medium may enter inlets(not illustrated) at the top and bottom of the housing 6 and bedischarged through an outlet 22 above the bulkhead 19 in the side wallof the housing and a corresponding outlet below the lower bulkhead. Thematrix in this embodiment passes twice through each bulkhead and at eachopening where it passes a bulkhead there is provided a seal 24comprising seal bars 25 and 26 engaging the outer and inner faces of thematrix under the bias provided by springs 27 and 28. The tracks 16 and17 are in close proximity to the outer ends of the matrix and, ifdesired, special sealing surfaces may be provided at these points.

The matrix is moved slowly along the supporting tracks by pairs ofrollers 32 disposed immediately ahead of each seal 24. These aresupported on the housing and they have shafts extending from the housingto be driven by any suitable means. As illustrated in FIGURE 1, theshafts 33 of the rollers of each pair bear pulleys which areinterconnected by crossed belts 34. Belts 35 connect the pairs ofdriving rollers and one of the shafts has a connection (not illustrated)to suitable means for driving all the rollers slowly. All the belts arepreferably of a positive drive type. Means such as spring 37 bias therollers together and thus into contact with the matrix. The mode ofoperation of the device illustrated in FIG- URES 1 and 2 should be clearfrom the foregoing, but may be described briefly. One medium, such ascooling air, is passed through the matrix from inlet 9 to outlet 10 andthe other medium, such as compressor discharge air, flows radiallythrough the end loops of the matrix. The rollers 32 are drivenconcurrently and slowly propel the matrix in its circuit of the guidingtracks by frictional engagement with the matrix. The matrix passesthrough the bulkhead seals 24 immediately beyond each set of drivingrollers and the pushing force of the rollers closes the cells of thematrix as illustrated at 39 in FIGURES 2 and 4, where it passes throughthe seal. The traction of the next set of drive rollers expands thematrix in the succeeding path until it reaches the rollers where it isagain collapsed where it passes through the cells. Thus, the two fluidscan flow readily through the expanded matrix and are squeezed out of thematrix to a very large extent before it passes through the seals.

FIGURES 3 and 4 illustrate features not shown in FIGURES 1 and 2. Thematrix is a chain of segments, each segment consisting of a number ofleaves 19 disposed between two rigid end sheets 40. The sheets 40provide partitions between the adjacent segments. Also,

a lost motion push-pull connection is provided between adjacentpartitions which limits the amount of expansion and contraction of thecellular material of the matrix.

The partitions 40 have bumpers 42 extending from them at each face andedge of the matrix, as shown at the top of FIGURE 4 and in FIGURE 3. Thebumpers 42 are in engagement where the matrix passes through the seal,and also the bumpers 42 at the radially inner side of the matrix are inengagement as it passes around the curved portions of the track. Thebumpers thus provide a means other than the matrix leaves to limit thedegree of contraction of the matrix, and also to transmit the "pushingforce where the matrix goes through the seal.

There is also a lost-motion tension connection provided by bent wirepieces 44 which extend through holes in the partition at each edge ofthe matrix. The rods 44 have bent-over ends 45 which define heads tolimit their movement from the partition and each rod 44 includes a loop46 which encircles a companion rod 44. In the lower part of FIGURE3,.the tension conection is fully extended with the heads 45 against thepartitions 40,

invention to explain the principle thereof is not to be considered tolimit the invention, since many modifications may be made by theexercise of skill in the art.

I claim: 1. A regenerator comprising, in combination: a continuousmatrix of expansible and contractible porous structure a bulkhead havingat least one opening for passage of the matrix means for moving thematrix progressively through the opening and means for compressing thematrix in the direction of movement thereof to contract the matrix atleast partially at the opening so as to minimize carrythrough of fluidby the matrix. 2. A regenerator as recited in claim 1 in which the 4means for compressing the matrix includes a seal in frictional contactwith the matrix at the opening.

3. A regenerator as recited in claim 1 in which the means for moving thematrix through the opening is a pair of friction drive rollers engagingopposite faces of the matrix.

4. A regenerator as recited in claim 1 in which the matrix comprises aseries of segments each segment having a plural number of flexiblecorrugated sheets dei'lning passages between the sheets.

5. A regenerator as recited in claim 4 including also rigid partitionsdisposed between the segments.

6. A regenerator as recited in claim 5 including also lost-motionpush-pull connections between the partitions limiting the range ofseparation of adjacent partitions.

7. A regenerator comprising, in combination:

a housing bulkhead means dividing the interior of the housing into atleast two spaces an endless matrix forming a loop means guiding thematrix for movement through the spaces and through openings in thebulkhead means a seal in frictional contact with the matrix at a saidbulkhead opening, and means adjacent to and ahead of the seal engagingto the matrix for driving the matrix the matrix having a structuredefining pas-sages through the matrix expansible and contractible in thedirection of movement of the matrix adapted to be contracted by frictionin the seals and expanded between the seals.

8. A regenerator as recited in claim 7 in which th 7 9. A regenerator asrecited in claim 8 in which the 9 matrix comprises thin flexiblecorrugated sheets bonded together to define a cellular structureexpansible and contractible by flexure of the corrugations.

10. A regenerator as recited in claim 7 in which the matrix comprises achain of expansible segments and rigid partitions disposed between thesegments.

11. A regenerator as recited in claim 10 including also lost-motiontension connections between the partitions.

12. A regenerator as recited in claim 11 including also bumpers defininga minimum space between the partitions.

13. A regenerator as recited in claim 10 including also bumpers defininga minimum space between the partitions.

References Cited UNITED STATES PATENTS 2,836,398 5/1958 Linderoth '9 X2,866,624 12/ 1958 Holmquist 165-6 2,915,297 12/1959 Lange 165--93,155,151 11/1964 Pouit 165-6 FOREIGN PATENTS 919,596 2/1963 GreatBritain.

ROBERT A. OLEARY, Primary Examiner.

A. W. DAVIS 1a., Assistant Examiner.

1. A REGENERATOR COMPRISING, IN COMBINATION: A CONTINUOUS MATRIX OFEXPANSIBLE AND CONTRACTIBLE POROUS STRUCTURE A BULKHEAD HAVING AT LEASTONE OPENING FOR PASSAGE OF THE MATRIX MEANS FOR MOVING THE MATRIXPROGRESSIVELY THROUGH THE OPENING AND MEANS FOR COMPRESSING THE MATRIXIN THE DIRECTION OF MOVEMENT THEREOF TO CONTACT THE MATRIX AT LEASTPARTIALLY AT THE OPENING SO AS TO MINIMIZE CARRYTHROUGH OF FLUID BY THEMATRIX.